Diffusion Angle - Any guru's know?

A stupid quesion I suppose, but how is this referenced? Center line to edge, or edge to edge? Since once's twice the degree of the other it would seem to matter.

If I'm not clear, lets say I want 4' of beam width at a distance of 10'. That's about 22 degrees edge to edge, or about 11 center to edge. so I either want a 10 degree diffuser (not so hard to get) or a 20, (should such a thing exist..)

Any takers?

LED manufacturers tend to give half beam width in degrees, but I'm not certain about diffusers. Is there a specific manufacturer that you could give as a reference?

Regards,
Eric

I should preface this by saying I've never looked at diffusers that labeled what angle they would spread a beam, so don't take my word for this.

The only potential useful experience I have is with a Malkoff M60LF drop-in. Now, this may not apply since the optic is making the flood, not a separate diffuser. However, it's a "25 degree flood". Doing my own visual guesstimations, I don't see that there's any way this 25 degree angle could be measuring center to edge. I'm 97% certain that this 25 degree "diffusion optic", if you could call it that, is measured from edge to edge.

So, I don't know if diffusers are measured the same as optics, but I'd put my money on them advertising edge to edge. Hopefully someone with actual knowledge can confirm that, though.

Ledil optics are referenced from center to edge. I think that they don't have model with exactly 10°(20° overall) beam, but for example Rocket-M 13°(26° overall) might do the job? I've made beamshots with some ledil optics and they have very nice smooth beam.

Thank you guys:

I'd spotted a 3rd party article stating LED manufactures rate edge to center as well, nice to have it confirmed. I suppose we can extend that to at least a supposition that it should be that way for difffusers

Still, I half suspect there are company's out there doing otherwise. The Lowes/Cree light is supposedly an 8 degree optic. I'd have to guess more like 5. I'll probably measure it tonight.

25 degree flood? Wow that's wide. If that's center to edge it would be around (SWAG) 10' at a depth of 10'. If edge to edge around 5' @ 10' away.

I'm not sure what manufactere to reference. I'm trying to get a true 10-15 degree beam spread on 7090 Crees. I'm using DX C-3's and the Lowes as test mules to get what I want. it seems the reflector focuses a very tight beam and a very wide loose spill. I'd prefer a tight spill, no beam.

Yes, the beam shots have some VERY NICE patterns. Sadly, I don't even recognize the language, much less speak it. (ah, yes, another example of a quality US education. ). Are those optics available in the US and in varying sizes?

My most sincere thanks for the help and any other insights.

regards,

dan

Those are Ledil optics.
www.ledil.fi


Brum have had few groupbuys, here on the marketplace. I think he still have few optics left.

http://www.cpfmarketplace.com/mp/showthread.php?t=175502


Edit: Brum's nick corrected .

25˚ optics aren't hard to find.

25˚ optics aren't hard to find.

Click to expand...

Maybe for you! I don't have the force to find one... Linkage?

I see the ledil guys use a measurement, FWHM that amounts to edge to edge. Another side of the story.

And I've measured the spot on the lowes-cree (that is rumored to be @8 degrees). Just under 8 degrees edge to edge.

ledil doesn't have the size I need. any other suggestions?

dfischer said:

Maybe for you! I don't have the force to find one... Linkage?

I see the ledil guys use a measurement, FWHM that amounts to edge to edge. Another side of the story.

And I've measured the spot on the lowes-cree (that is rumored to be @8 degrees). Just under 8 degrees edge to edge.

ledil doesn't have the size I need. any other suggestions?

Click to expand...

Cutter has a bunch in the 18-25˚ range.

Khatod has 23.5mm dia(part no. KEPL112725 - in case the link doesn't work) and 35mm dia 25˚ optics. I don't know how the 35mm ones mount.

dfischer said:

Sadly, I don't even recognize the language, much less speak it. (ah, yes, another example of a quality US education. ). Are those optics available in the US and in varying sizes?

My most sincere thanks for the help and any other insights.

regards,

dan

Click to expand...

I didn't expect that you will understand the language but I hope that images are understandable to everyone

dfischer said:

I see the ledil guys use a measurement, FWHM that amounts to edge to edge. Another side of the story.

Click to expand...

No, this is image from CRS-SS 7° datasheet:


As you can see they measure beam width from center to edge.

As Jesseri suggested try contacting Brum
http://www.cpfmarketplace.com/mp/showthread.php?t=175502
I also bought optics from him.